The 12th series of the BBC One show, presided over by John Torode and Gregg Wallace, scored an average of 4.4 million viewers, a peak of 4.6 million and a 23% audience share when it aired from 8pm until 9pm on Wednesday.
This is more than one million up from last year's series, which opened with an average of 3.3 million viewers in June 2016.
This data is based on overnight ratings, which do not account for those watching on catch up.
Wallace took to Twitter to share his joy over the ratings.
He wrote: "Lovely to see people enjoying Celeb MC in record numbers. Thank you xx."
The first instalment of the series saw former snooker champion Stephen Hendry knocked out after putting forward a disappointing halibut and pancetta dish.
He was up against comedian Jim Moir - better known as Vic Reeves, TV presenters Angellica Bell and Julia Somerville and French tennis star Henri Leconte.
The broadcast happened just hours after the BBC announced it would be moving another of its food programmes, The Big Cooking Showdown, in the schedule to avoid a clash with Channel 4's The Great British Bake Off, which will debut on Tuesday August 29.
The current series opener was just shy of the final episode of last year's series, which saw presenter Alexis Conran crowned the champion.
An average of 4.9 million tuned into the episode on July 29 2016, with a peak of 5.7 million.
:: Celebrity MasterChef continues on Friday August 18 at 8.30pm on BBC One.